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Apert syndrome is a congenital craniosynostosis syndrome characterized by premature fusion of cranial sutures, midfacial hypoplasia, and syndactyly of hands and feet.

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https://www.youtube.com/watch?v=Vsa0dX-s-po

It represents one of the classic acrocephalosyndactylies, along with Crouzon and Pfeiffer syndromes, but is distinguished by complex syndactyly (“mitten hand” deformity).

Radiologically, it is a craniofacial dysostosis associated with FGFR2 mutation, leading to abnormal bone differentiation and early ossification of sutures.

Etiology and Genetics

Gene: FGFR2 (Fibroblast Growth Factor Receptor 2) mutation.
Chromosome: 10q26.
Inheritance: Autosomal dominant (often sporadic, related to paternal age effect).
Pathogenesis:
- Gain-of-function mutation in FGFR2 → premature differentiation of osteogenic cells in sutures → early cranial suture fusion and abnormal bone formation.
- Abnormal signaling also affects limb and facial mesenchyme, leading to syndactyly and midfacial hypoplasia.

Epidemiology

Incidence: approximately 1 in 65,000–80,000 live births.
No sex predilection.
Often diagnosed at birth or prenatally on detailed fetal ultrasound or MRI.

Clinical Features

System	Characteristic Findings
Craniofacial	Premature closure of coronal sutures → acrocephaly (tower skull) or brachycephaly; frontal bossing, flat occiput, high forehead.
Facial Skeleton	Midface hypoplasia, shallow orbits → proptosis, hypertelorism, beaked nose, hypoplastic maxilla with relative mandibular prognathism.
Hands/Feet	Complex syndactyly (fusion of soft tissues and bones, typically digits 2–4): “mitten hand” or “spoon hand.” Feet show similar fusion of toes (“sock foot”).
Dental/Oral	High-arched palate, dental crowding, cleft palate (~30%).
CNS / development	Variable intellectual disability, hydrocephalus, Chiari I malformation, corpus callosal anomalies, and increased intracranial pressure from craniosynostosis.
ENT/Respiratory	Narrow nasal passages, choanal stenosis, upper airway obstruction, recurrent otitis media, possible sleep apnea.
Cardiovascular / genitourinary	Occasionally congenital heart or renal anomalies.

Etiology and Genetics

Epidemiology

Clinical Features

Pathophysiology